In telecommunications applications, and particularly in satellite communications, an antennae reflector is normally used to gather and focus the electromagnetic radiation being emitted from the spacecraft to earth. Furthermore, the same reflectors are used to transmit electromagnetic radiation back into space.
Reflectors having a diameter greater than three meters are usually too large to be carried efficiently on mobile equipment. Therefore, such reflectors are typically sectioned to allow them to be collapsed or folded for transport on public roads. During the process of sectioning the reflector, a substantial amount of surface quality is lost, resulting in a less efficient reflector. This loss of surface quality is particularly critical in view of the ever-decreasing orbital spacing between satellites. Presently, the spacing between adjacent satellites may be as little as two degrees azimuthally. Therefore, any loss in the directional capability of the antennae reflector cannot be tolerated. Recent Notices of Inquiry and Proposed Rulemaking (FCC Docket No. 81-204) by the Federal Communications Commission have rendered these variations in surface quality unacceptable.
The ability of a parabolic reflector to meet the standards of the Federal Communications Commission is based upon the shape of the reflector conforming to an exact mathematical equation. The manufacturing processes and the forces involved in producing this shape from a metal sheet result in variations and discontinuities in the resultant surface from the shape desired. Inspection of the surface and testing of the reflector is used to determine its suitability to meet applicable performance standards. The reflector should have the ability to absorb residual stresses inherent in the manufacturing process so that the resultant strain and distortion in the surface does not appreciably affect its efficiency and performance.